/*
 * Copyright (c) 2023, 2023, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package com.oracle.svm.core;

import org.graalvm.nativeimage.ImageSingletons;

import com.oracle.svm.core.util.VMError;

import jdk.graal.compiler.api.replacements.Fold;
import jdk.vm.ci.code.Register;

public class SubstrateControlFlowIntegrity {

    public enum CFIOptions {
        NONE,
        HW,
        SW,
        SW_NONATIVE
    }

    public CFIOptions getCFIMode() {
        return CFIOptions.NONE;
    }

    public Register getCFITargetRegister() {
        throw VMError.shouldNotReachHere("No CFI Target Register is available");
    }

    public boolean continuationsSupported() {
        return true;
    }

    @Fold
    public static SubstrateControlFlowIntegrity singleton() {
        return ImageSingletons.lookup(SubstrateControlFlowIntegrity.class);
    }

    @Fold
    public static boolean enabled() {
        var cfiMode = singleton().getCFIMode();
        return cfiMode != CFIOptions.NONE;
    }

    @Fold
    public static boolean useSoftwareCFI() {
        var cfiMode = singleton().getCFIMode();
        return cfiMode == CFIOptions.SW || cfiMode == CFIOptions.SW_NONATIVE;
    }
}
